The present invention refers to a clamping apparatus for fixing a collet member to a chuck member.
With the expression “Collet Member”, in the present context, a slotted clamping sleeve member is understood, having a conical portion, which is adapted to clamp an object, particularly a work piece to be machined, by radially forcing out or forcing in the clamping jaws of the collet member. Such collet members are used, for instance, with turning lathes where they have a female thread to be screwed onto a threaded spindle of the lathe.
A fundamental disadvantage of known conventional collet members consists in the fact that both their angular position around the rotational axis, i.e. the central longitudinal or Z-axis, as well as their position in the direction of the extension of the Z-axis is not or, at least, not exactly defined with regard to the position of the spindle. In machining axially symmetrical work pieces in a lathe, the aforementioned disadvantage is of secondary importance. However, more and more often the need arises to clamp work pieces to machine tools other than lathes that are not axially symmetrical by means of collet members; in this case, the exact definition of the position of the work piece not only in X- and Y- direction, but also in Z-direction, i.e. along the extension of the central longitudinal axis, as well as with regard to their angular orientation around the Z-axis is highly desirable.
Hitherto, in order to use collet members in a positionally well defined manner, i.e. both in X- and Y-directions as well as in Z-direction and regarding the angular orientation around the Z-axis, intermediate pallet members had to be used to which the collet member is fixed and which are provided with positioning or centering elements. That pallet member, then, can be attached to a corresponding chuck member provided with positioning or centering elements cooperating with the elements of the intermediate pallet member.